Method of flotation of oxides



Patented Jan. 17, 1933 w UNITED STATES PATENT OFFICE LUDWIGJ. CHBISTM ANN, OF JERSEY CITY, AND STUART A. FALCONEB, OI ELIZABETH,

NEW JERSEY, ASSIGNORS TO AMERICAN CYANAMID COMPANY, OF NEW YORK,

N. 32"., A CORPORATION OF MAINE METHOD FLOTATION OF OXIDES No Drawing.

This invention relates to the froth flotation of ores, more particularly to the application in froth flotation of certain types of promoters which have very desirable properties and high efficiency in the flotation operation.

It is among the objects of the present invention to separate oxidized minerals from ores containing the same." Many reagents are known which act as promoters for sulphide ores, but very few of such sulphide reagents are effective in the flotation of oxide minerals. On the other hand, such reagents as are effective for oxidized minerals are in general suitable for the flotation of sulphides. By oxidized minerals we include compounds of heavy metals, such as lead, zinc, copper and the like with elements or groups of elements other than sulphur, such as in the form of oxide, hydroxide, carbonate and the like.

The present invention is based upon the discovery that alkaline metal salts of certain thiazoles are effective reagents in the froth flotation of oxide ores. A large number of reagents are included in this class, many of which have complicated formulae. These reagents are preferably used in. combination with other previously known reagents, but under many circumstances eflicient flotation of oxidized minerals may be obtained by these reagents alone. As-an example, of the substances included in the present invention the potassium salt of 4 phenyl 5 thioketo 2 mercapto 1.3.4 thiodiazole has been used. This compound may be prepared as described in the literature, and briefly as follows:

55 g. of phenylhydrazine hydrochloride, 165 g. of ethylalcohol and 100 g. of carbon bisulphide were weighed into a flask, fitted with a reflux. A solution of 70 g. of potassium hydroxide in 250 cc. of ethylalcohol was added. The reaction mixture assumed an orange color. It is heated on the steam bath until no more H S is evolved (10 hours), filtered hot, and cooled. Long feathery,

Application filed February 20, 1930. Serial No. 430,134.

golden yellow crytals are filtered off. The mother liquor may be concentrated and a further quantity of product obtained.

The structural formula of the class of compounds of which 4 phenyl 5 thioketo 2 mercapto 1.3.4 thiodiazole is a member may be written as follows:

' mill charge was transferred to a sub-aeration The mesh of machine and diluted to 22% solids. The re.

agents were added to the machine and a mineralized froth collected for 20 minutes.

Reagents ln lbs. per ton of ore Ammonium dibutyl dlthlophosphate 1. Po t assipm 4 phenyl 5 thioketo 2 mercapto 1.3.4 thio- Crude monoammonium phosphate Per cent lead in heads Per cent lead in concentrates. Per cent lead in tails Per cent lead recovered a it sole promoters we preferably utilize them in combination with other well-known flotation reagents. As an example, of this group of compounds, we have used the sodium salt of 6 dimethyl amino 2 mercapto benzothiazoles as flotation reagents for oxidized minerals.

The structural formula of the class of compounds to which this belongs may be written asfollows:

has.

by an alkaline metal, such as sodium, potas-' slum, ammonium, calcium or the like.

A specific compound may be produced in the following manner:

1 mol. of 1 amino 2 mercapto 4 dimeth laminobenzol, 1 mol. of caustic (as 25% so ution) and 1 mol. of carbon bisulphide are refluxed for several hours. The solution is yellow colored. On precipitation with acid 6 dimethylamino-2-mercaptobenzothiazole is precipitated.

The following is an example of the use of one of the compounds of this class in the flotation of an oxide lead ore, in which the lead is principally in the form of carbonate:

1200 g. of minus ten mesh ore, 1200 g. of water and 5.0 lbs. of crude monoammonium phosphate per ton or ore were ground in a steel rod mill for 12 minutes. The mesh of the feed was 60% minus 200 mesh. The rod mill charge was transferred to a sub-aeration machine and diluted to 22% solids. The reagents were added to the machine and a min- I eralized froth collected for 20 minutes.

Reagents in lbs. per ton Sodium 6 chlor 2 memptobenzothiazole--- Ammonium di n-butyl dithiophosphate. Crude monoammonlum phosphate Per cent lead in heads Per cent lead in rates Per cent lead in tails Per cent lead recovered Reagents in lbs. per ton of ore Sodium di-butyl dithiophosphate Sodium 6 dimethylamino 2 mercaptobenzothlazole. Crude moneammonium phosphate Per cent lead in heads Per cent lead in concentrates Per cent lead in tails Per cent lead recovered the concentratesi whereas by the use of reagents previous y known, the recovery is low. The specific compounds given above are merely illustrative of every large number of specific compounds which are included in the present invention and which may be used with excellent results. Although the other promoter used in conjunction with our new promoters isstated in our exam Is to be a dithiophosphate, it is not at al necessary to use a dithiophosphate as it may be omitted, or may be replaced by other dithiophosphates or even by other types of known flotation promotors, such as the xanthates. The essential feature of our invention is the use of alkaline salts of thiazoles as promoters, either alone or in conjunction with other promoters as set forth in the claims appended hereto.

What we claim is: 1 v

1. A method of recovering minerals from ores which comprises subjecting an oxidized ore to a froth flotation operation in the presence of an alkaline salt of a thioketo merca-ptothiodiazole as a promoter.

2. A method of recovering minerals from ores which comprises subjecting an oxidized ore to a froth flotation operation in the presence of an alkaline salt of a substituted thioketo mercaptothiodiazole as a promoter.

3. A method of recovering minerals from ores which comprises subjecting an oxidized ore to a froth flotation operation in the pres ence of an alkaline salt of an aryl thioketo mercaptothiodiazole as a promoter.

4. A method of recovering minerals from ores which comprises subjecting an oxidizedore to a froth flotation operation in the presence of an alkaline salt of a phenyl thioketo mercaptothiodiazole as a promoter.

' In testimony whereof, we have hereunto subscribed our names this 18th day of February, 1930.

LUDWIG J. CHRISTMANN. STUART A. FALCONTER. 

